Early in Koike's career, he studied under
Takao Saito. He began his manga career at Saito Production in 1968, working on series such as
Muyōnosuke and as a founding scriptwriter for
Golgo 13. Koike, along with artist
Goseki Kojima, made the manga
Lone Wolf and Cub, and Koike also contributed to the scripts for the 1970s film adaptations of the series, which starred famous Japanese actor
Tomisaburo Wakayama. In 1992 he himself produced a
Lone Wolf and Cub film,
Lone Wolf and Cub: Final Conflict which starred
Masakazu Tamura. Koike and Kojima became known as the "Golden Duo" because of the success of
Lone Wolf and Cub. In the 1970s, Koike was exceptionally prolific, working on dozens of manga series. Notable collaborations from this period include
Secretary Bird with
Monkey Punch (1970), a story with
Kazuo Umezu (1973), and
Hanappe Bazooka with
Go Nagai (1979-82). He also founded Studio Ship (later Koike Shoin) in 1972 as a production house and publisher. In 2011, Koike announced his intention to write a
magical girl manga series titled
Maho Shojo Mimitsuki Mimi no QED. On April 17, 2019, Kazuo Koike died due to
pneumonia at the age of 82. His death happened just five days after the death of fellow prolific manga artist
Monkey Punch on April 11, who also died of pneumonia and who Koike considered his rival in the
Weekly Manga Action magazine. == Themes ==